• Journal of Pharmaceutical Investigation
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• 제38권5호
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• pp.313-317
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• 2008

This study investigated the effect of naringin, a flavonoid, on the bioavailability of etoposide administered orally to rats. Etoposide (6 mg/kg) was administered orally to rats alone or with naringin (1, 4 or 12 mg/kg). Compared with the control group, the co-administration of etoposide with 4 and 12 mg/kg of naringin significantly (p<0.05) increased the area under the plasma concentration-time curve (AUC) and the peak plasma concentration ($C_{max}$) of the oral etoposide. Consequently, the absolute bioavailability (AB) of etoposide in the presence (4 and 12 mg/kg) of naringin was significantly (p<0.05) increased by $9.4{\sim}10.6%$ compared with the control group (7.4%). The relative bioavailability (RB) of etoposide was increased 1.13- to 1.44-fold compared to the control group. Enhanced bioavailability of etoposide might be due to inhibition of both cytochrome P450 (CYP) 3A4 in the intestine or liver and P-glycoprotein (P-gp) transport efflux of etoposide in the intestinal membrane. This data indicate that careful consideration of the dosage for therapy with etoposide is required in a case of clinical application of the co-administration of etoposide and naringin.

• 생명과학회지
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• 제17권9호통권89호
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• pp.1204-1210
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• 2007

Totopoisomerase II 저해제인 etoposide는 핵안에 DNA double strand breaks를 일으키므로써 세포의 DNA에 손상을 초래한다. 본 연구에서는 인간 망막색소상피세포인 ARPE-19 세포에서의 세포성장 및 아폽토시스에서 etoposide의 역할을 살펴보았다. Etoposide는 세포의 성장을 크게 감소시켰으며 TUNEL에서 아폽토시스를 나타내는 DNA fragmentation의 증가를 유도하였다. 게다가, etoposide는 산화적 손상에 대해 세포나 조직을 보호하는 역할을 하는 것으로 알려진 세포내 항산화효소인 heme oxygenase-1 (HO-1)의 발현을 크게 증가시켰다. Etoposide에 의한 HO-1 발현증가는 항산화물질 NAC에 의해 억제되었는데, 이는 etoposide에 의한 세포내 ROS의 증가가 HO-1 발현에 중요한 역할을 한다는 것을 의미한다. 또한 HO-1 발현을 억제하기 위하여 HO-1 siRNA 방법을 사용하였다. 흥미롭게도, HO-1 유전자의 knock-down은 etoposide에 의해 유도되는 DNA fragmentation의 정도를 증가시켰다. 이들 결과를 종합해볼 때, etoposide에 의해 자극되어진 ARPE-19 세포에서 발현증가된 HO-1은 etoposide에 의한 아폽토시스 유발과정에서 세포를 보호하는 항아폽토시스의 기능을 한다는 것을 시사한다.

• BMB Reports
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• 제55권3호
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• pp.148-153
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• 2022

Etoposide is a chemotherapeutic medication used to treat various types of cancer, including breast cancer. It is established that pulsed electromagnetic field (PEMF) therapy can enhance the effects of anti-cancer chemotherapeutic agents. In this study, we investigated whether PEMFs influence the anti-cancer effects of etoposide in MCF-7 cells and determined the signal pathways affected by PEMFs. We observed that co-treatment with etoposide and PEMFs led to a decrease in viable cells compared with cells solely treated with etoposide. PEMFs elevated the etoposide-induced PARP cleavage and caspase-7/9 activation and enhanced the etoposide-induced down-regulation of survivin and up-regulation of Bax. PEMF also increased the etoposide-induced activation of DNA damage-related molecules. In addition, the reactive oxygen species (ROS) level was slightly elevated during etoposide treatment and significantly increased during co-treatment with etoposide and PEMF. Moreover, treatment with ROS scavenger restored the PEMF-induced decrease in cell viability in etoposide-treated MCF-7 cells. These results combined indicate that PEMFs enhance etoposide-induced cell death by increasing ROS induction-DNA damage-caspase-dependent apoptosis.

• 한국미생물·생명공학회지
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• 제28권2호
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• pp.87-91
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• 2000

미생물로부터 U937 세포주의 etoposide에 유발된 apoptosis 저해물질을 탐색한 결과 곰팡이 F80834 균주를 선발하였다. 균주 배양액으로부터 저해물질을 분리한 후 UV, EIMS, 1H-NMR, 13C-NMR, DEPT 등의 기기분석을 실시한 결과 terrein으로 동정되었다. 이 물질은 $IC_{50}$ $20\mu\textrm{g}/ml$의 농도로 U937 세포주의 etoposide에 의한 caspase 3 유도를 저해하였다. Etoposide에 의한 세포의 사멸도 IC50 $10\mu\textrm{g}/ml$ 농도로 저해하였으며, 동일한 농도 조건에서 단독 처리시 세포 독성을 나타내지 않았다.

• Journal of Oral Medicine and Pain
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• 제30권2호
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• pp.231-238
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• 2005

항암제의 연구는 화학물질에 민감한 암세포를 죽음에 이르게 하는 세포자멸사와 같은 다양한 세포기능에 초점을 맞추어 왔다. 그러나 약물이 유도한 세포의 죽음에 있어서 핵심적인 분자적 기작은 아직 잘 이해되지 않고 있다. Etoposide는 폐암과 고환암에 사용되는 항암제로서, 본 연구는 etoposide가 사람구강편평상피암종세포(OSC9)에도 세포독성효과와 세포자멸사를 일으키는지를 알아보기 위해 실행하였다. 이 실험에서 etoposide는 농도와 시간 의존적으로 OSC9 세포의 생존율를 현저하게 저해시켰다. TUNEL 염색과 Hoechst 염색을 이용한 핵의 형태학적 관찰에서는 etoposide에 의해 핵이 응축되고 분절되었다. p53의 발현은 48 시간에 증가했으며, etoposide 처리로 인해 caspase-3의 활성을 관찰할 수 있었으며, 그 기질에 해당되는 PARP 단백질은 116-kDa과 89-kDa으로 분절되었다. 위의 결과들은 OSC9 세포에서 etoposide가 유도한 세포자멸사는 caspase-3의 활성과 관련됨을 설명하고 있다.

• BMB Reports
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• 제38권5호
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• pp.619-623
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• 2005

The efficacy of chemotherapeutic agents on tumor cells has been shown to be modulated by tumor suppressor gene p53 and its target genes such as Bcl-2 family members (Bax, Noxa, and PUMA). However, various chemotherapeutic agents can induce cell death in tumor cells that do not express the functional p53, suggesting that some chemotherapeutic agents may induce cell death in a p53-independent pathway. Here we showed that etoposide can induce the similar degree of cell death in p53-deficient HCT 116 cells, whereas 5'-FU-mediated cell death is strongly dependent on the existence of functional p53 in HCT 116 cells. Further, we provide the evidence that etoposide can induce the cytochrome c release from isolated mitochondria, and etoposide-induced cytochrome c release is not accompanied with the large amplitude swelling of mitochondria. These data suggest that etoposide can directly induce the mitochondrial dysfunction irrespective of p53 status, and it may, at least in part, account for the p53-independent pathway in cell death induced by chemotherapeutic agents.

• Tuberculosis and Respiratory Diseases
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• 제67권2호
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• pp.145-147
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• 2009

Etoposide is a semi-synthetic derivative of podophyllotoxin that is effective against many cancers including small cell lung cancer. We report a case of etoposide-induced anaphylaxis in a 51-year-old woman who tolerated etoposide during her first cycle chemotherapy regimen. During the second cycle, she complained of generalized urticaria and dyspnea 5 minutes after being infused with etoposide. She recovered completely with antihistamine, corticosteroid and fluid replacement. The intradermal skin test with etoposide showed a clear positive immediate reaction. This case suggests that etoposide can induce IgE-mediated anaphylaxis.

• Journal of Microbiology and Biotechnology
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• 제17권11호
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• pp.1856-1861
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• 2007

Physiological cell conditions such as glucose deprivation and hypoxia play roles in the development of drug resistance in solid tumors. These tumor-specific conditions cause decreased expression of DNA topoisomerase $II{\alpha}$, rendering cells resistant to topo II target drugs such as etoposide. Thus, targeting tumor-specific conditions such as a low glucose environment may be a novel strategy in the development of anticancer drugs. On this basis, we established a novel screening program for anticancer agents with preferential cytotoxic activity in cancer cells under glucose-deprived conditions. We recently isolated an active compound, AA-98, from Streptomyces sp. AA030098 that can prevent stress-induced etoposide resistance in vitro. Furthermore, LC-MS and various NMR spectroscopic methods identified AA-98 as mithramycin, which belongs to the aureolic acid group of antitumor compounds. We found that mithramycin prevents the etoposide resistance that is induced by glucose deprivation. The etoposide-chemosensitive action of mithramycin was just dependent on strict low glucose conditions, and resulted in the selective cell death of etoposide-resistant HT-29 human colon cancer cells.

• Archives of Pharmacal Research
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• 제29권11호
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• pp.1018-1023
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• 2006

Chemoresistance remains the major obstacle to successful therapy of cancer. In order to understand the mechanism of multidrug resistance (MDR) that is frequently observed in lung cancer patients, here we studied the contribution of MDR-related proteins by establishing lung cancer cell lines with acquired resistance against etoposide. We found that human H460 lung cancer cells responded to etoposide more sensitively than A549 cells. Among MDR-related proteins, the expression of p-glycoprotein (Pgp) and lung resistance protein (LRP) were much higher in A549 cells compared with that in H460 cells. When we established H460-R1 and -R2 cell lines by progressive exposure of H460 cells to increasing doses of etoposide, the response against etopbside as well as doxorubicin was greatly reduced in R1 and R2 cells, suggesting MDR induction. Induction of MDR was not accompanied by a decrease in the intracellular accumulation of etoposide and the expression of MDR-related proteins that function as drug efflux pumps such as Pgp and MRP1 was not changed. We found that the acquired resistance paralleled an increased expression of LRP in H460 cells. Taken together, our data suggest the implicative role of LRP in mediating MDR in lung cancer.

• Molecules and Cells
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• 제28권6호
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• pp.509-513
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• 2009

Here, we show that JNK1 and JNK3 have different roles in ${\alpha}-$ or etoposide-induced apoptosis in HeLa cells. Dominant negative JNK1 inhibited $TNF-{\alpha}-$ or etoposide-induced apoptosis, while dominant negative JNK3 promoted $TNF-{\alpha}-$ or etoposide-induced apoptosis. During $TNF-{\alpha}$-induced apoptosis, JNK1 was activated in a biphasic manner, exhibiting both transient and sustained activity, whereas JNK3 was activated early and in a transient manner. The role of JNK3 activation was an anti-apoptotic effect, while the role of JNK1 activation was a pro-apoptotic effect. These results suggest that the anti-apoptotic mechanism of JNK3 in $TNF-{\alpha}$-induced apoptosis originates before the apoptotic machinery is triggered.